Already working on it. In my case, I'm basically taking around 30 Alpha Centauri techs, and tweaking a bit. Plus, adding maybe 10 of my own, to include things like Mecha, power armor, energy shields, zombies, genetically engineered dragons, futuristic naval vessels, that sort of thing. A few things are rearranged, too; since there's no need to duplicate AC's techs for rovers, jets, and copters, I moved the anti-grav stuff up much earlier (hovertanks just before Fusion, gravships just after).
The bigger problem is this: when's the last time you played a Civ game where you actually REACHED the Future Techs? Most games are decided long before that point; if I ever reach Modern Armor, it's only because I've either been toying with my opponents, or I'm just mopping up. Or a Scenario, of course.